1. 2019;22;E181-E190Prevalence of Extreme Trait Sensory Profiles and Personality Types in Nonspecific Chronic Low Back Pain with Predominant Central Sensitization: Secondary Analysis of an International Observational Study
   Observational Study
   Paul Holmes, PhD, Gillian Yeowell, PhD, Peter C. Goodwin, PhD, Keith Smart, PhD, Jo Nijs, PhD, and Jacqui R. Clark, PhD.

BACKGROUND: Individuals with nonspecific chronic low back pain (NSCLBP) and central sensitization (CS) exhibit sensory hypersensitivity that may be related to pre-existing trait characteristics. Sensory profiles and trait anxiety-related characteristics have sensory sensitivity in common with CS.

OBJECTIVES: The objectives of this study were 1) to observe the prevalence of 4 personality types and extreme scores of 4 trait sensory profiles in people with NSCLBP and predominant CS; and 2) to compare these between 2 subgroups based on high and low self-reported CS symptoms.

STUDY DESIGN: An international cross-sectional observational study was undertaken.

SETTING: Adults (n = 165; mean age = 45 ± 12 standard deviation) were recruited from physiotherapy clinics across 3 countries and 2 continents.

METHODS: The inclusion criteria were: NSCLBP, aged 18-64 years, with clinically identified predominant CS pain, without specific pathology. The outcome measures were: Central Sensitization Inventory (CSI), Adolescent/Adult Sensory Profile, State/Trait Anxiety Inventory, and Marlowe Crowne Social Desirability Scale. Descriptive and comparative statistics were used.

RESULTS: CSI scores ranged from 19-79 (mean = 50). There was a high prevalence of extreme 1) trait sensory hyper- and, unexpectedly, hyposensitivity profile scores (P < 0.001) and Defensive High Anxious personality type (P < 0.01) in the high-CSI (CSI >= 40; 78%) subgroup, and 2) trait sensory hyposensitivity profile scores (P < 0.01) and Repressor personality type (P < 0.01) in the low-CSI subgroup (CSI < 40; 22%).

LIMITATIONS: Self-report measures only were used; limited demographics.

CONCLUSIONS: To our knowledge, these results are the first to demonstrate extreme trait sensory profiles and personality types in people with NSCLBP and predominant CS. A subgroup who reports low levels of CS symptoms may have a hyposensitive sensory profile and Repressor personality type. Further study is required to investigate the extent to which these trait characteristics may predict CS symptoms in people with NSCLBP.

KEY WORDS: Central sensitization, nonspecific chronic low back pain, prevalence of extreme trait characteristics, sensory profiles, trait anxiety-related personality types